Layer Basics

A large number of the manipulations you’ll perform in Photoshop involve layers. One of the benefits of working with layers is that you can edit a part of an image that is on a layer while the other layers remain unchanged. This is good news because it means that you can protect portions of an image while radically changing parts of the same image.

Each Photoshop image must have at least one layer and can have an almost unlimited number of layers. You select and manipulate layers by using the tools provided in the Layers palette.

Figure 8-1 shows an image with four layers. Each image — the paint and brushes, colored pencils, and crayons — is on its own layer. The fourth layer is the Background. These four layers are shown in the Layers palette. The layers are shown from top to bottom with the Background layer (which is behind the three layers) at the bottom of the list. This is the stacking order.

The stacking order is very important because it determines the appearance of a final image. The layer that is at the top of the list in the Layers palette (at the top of the stacking order) appears in front of all the other layers.

To imagine how the stacking order works suppose you have a Photoshop image with two layers. One layer shows a pink rabbit and the other layer is solid black. If the rabbit layer is above (or on top of) the black layer, then you can see the rabbit. On the other hand, if the black layer is above (or on top of) the rabbit layer, then the rabbit will not be visible.

Remember

In order to preserve layers in an image, you must save the image file in either the Photoshop PSD or the special Photoshop TIF and PDF formats. Saving the image in any other format will automatically flatten the layers into a single layer. (For more about file formats, turn to Chapter 3.)